From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CF4DF44AB68; Tue, 21 Jul 2026 21:27:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669230; cv=none; b=DNxZuZfxlfIkZCgKkxQreFIL3EI2ZxqdOlhwe/gia1vHWuH0f99/Ouz7b0tMVqr4dTjRHG3Li/ijGuSiZ0q8XsHJhxTe85GaDLWRophYA1UWsnIQjFK7L+UKSg57WHVmyZgvbj43USxa3YsW6yXk4f2plND0JhhgtwaWScrpbNs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784669230; c=relaxed/simple; bh=++YsA2ZJzTBiZtOIfhr43NP/jeeyl3b4WUFG4FK/koM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CZdCroUI+A/1Pjluj/R/p1FQb7GH90wLTVz2PcotGbRFrS/ueSxzzms3icatyZ3q5hvDpb6Q2YboY3AxFt3FK/ErMXSV3cLaBFJaetYwClCREjsF2aRLFahHCrhi5MBhcli+JU77Y8Q+RU1rZAulDrgI+yKqW0Cb9Cgfp02A6aY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1GSDw7EI; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="1GSDw7EI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3E31D1F000E9; Tue, 21 Jul 2026 21:27:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784669229; bh=JpzKVEY2ONA2KGgLjYqGM6JCAljw4UwtN4eV1Hpn42A=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1GSDw7EIAvXqV+0us7PKC76cab/RB2D6l3hR3g0rv8FXfzAve5p4nH7lBKtnnfRAP sloKZLD6RLuu09DkFPGdc2TVW6HZR3wUVgA6xzObgrF2g8gVk89MR6tmkKN5qLCoo/ FhJG4ksn2/zdnifsqSHtSUwwEJtSGGSd+xCaxdpY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Guangshuo Li , Namjae Jeon , Steve French , Sasha Levin Subject: [PATCH 6.1 0469/1067] ksmbd: fix use-after-free in same_client_has_lease() Date: Tue, 21 Jul 2026 17:17:50 +0200 Message-ID: <20260721152435.108213946@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152424.521567757@linuxfoundation.org> References: <20260721152424.521567757@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Guangshuo Li [ Upstream commit 65b655f65c3ca1ab5d598d3832bb0ff531725858 ] same_client_has_lease() returns an opinfo pointer from ci->m_op_list after dropping ci->m_lock without taking a reference. smb_grant_oplock() then dereferences that pointer in copy_lease() and when checking breaking_cnt. A concurrent close can remove the old lease from ci->m_op_list and drop the last reference before the caller uses the returned pointer, leading to a use-after-free. Take a reference when same_client_has_lease() selects an existing lease, drop any previous match while scanning, and release the returned reference in smb_grant_oplock() after copying the lease state. Fixes: e2f34481b24d ("cifsd: add server-side procedures for SMB3") Signed-off-by: Guangshuo Li Acked-by: Namjae Jeon Signed-off-by: Steve French Signed-off-by: Sasha Levin --- fs/smb/server/oplock.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/smb/server/oplock.c b/fs/smb/server/oplock.c index 258ed9978b90e7..df3cc4d457f9ac 100644 --- a/fs/smb/server/oplock.c +++ b/fs/smb/server/oplock.c @@ -534,7 +534,12 @@ static struct oplock_info *same_client_has_lease(struct ksmbd_inode *ci, ret = compare_guid_key(opinfo, client_guid, lctx->lease_key); if (ret) { + if (!atomic_inc_not_zero(&opinfo->refcount)) + continue; + if (m_opinfo) + opinfo_put(m_opinfo); m_opinfo = opinfo; + /* skip upgrading lease about breaking lease */ if (atomic_read(&opinfo->breaking_cnt)) { read_lock(&ci->m_lock); @@ -1253,6 +1258,7 @@ int smb_grant_oplock(struct ksmbd_work *work, int req_op_level, u64 pid, if (atomic_read(&m_opinfo->breaking_cnt)) opinfo->o_lease->flags = SMB2_LEASE_FLAG_BREAK_IN_PROGRESS_LE; + opinfo_put(m_opinfo); goto out; } } -- 2.53.0